morusin and Lung-Neoplasms

Due to drug resistance and side effects, the development of novel therapeutics for the treatment of lung cancer is still in an urgent need. Morusin, a naturally occurring prenylated flavonoid isolated from the root bark of Morus alba, has been reported to be a promising candidate for cancer treatment including lung cancer. This study aimed to validate the anti-cancer effects of morusin in human non-small cell lung cancer (NSCLC) cell lines A549 and NCI-H292. The results indicated that morusin had growth inhibitory, pro-apoptotic and pro-autophagic effects on A549 and NCI-H292 cells. The induction of apoptosis was characterized by chromatin condensation and PARP cleavage. Mitochondrial membrane potential (MMP) loss, cytochrome c release, Bax/Bcl-2 dysregulation, and caspase-3 cleavage were also observed, indicating a mitochondria-dependent apoptosis was induced by morusin. A pro-autophagic effect was demonstrated by the increased level of LC3-Ⅱ and decreased level of SQSTM1/p62. Furthermore, morusin inhibited PI3K/Akt signaling and activated JNK, ERK pathways as indicated by the alteration in the ratio of phosphorylation level over total protein expression level. A PI3K/Akt inhibitor (LY294002), a JNK inhibitor (SP600125) and a MEK/ERK inhibitor (U0126) contributed to the determination that these pathways were involved in both apoptosis and autophagy induced by morusin. Moreover, morusin treatment strikingly enhanced intracellular ROS level, an ROS scavenger NAC blocked cell death and changes of Akt, JNK and ERK induced by morusin.

Topics: Apoptosis; Autophagy; Caspase 3; Cell Line, Tumor; Cell Proliferation; Chromones; Extracellular Signal-Regulated MAP Kinases; Flavonoids; Humans; JNK Mitogen-Activated Protein Kinases; Lung Neoplasms; Membrane Potential, Mitochondrial; Morpholines; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Signal Transduction; Transcription Factor RelA

The present study aimed to examine the inhibitory effects of morusin on the human lung cancer cell line A549. Various doses of morusin were applied to A549 cells and the effects were assessed by wound‑healing and MTT assays, flow cytometry analysis of apoptosis, a mitochondrial membrane potential assay and RT‑PCR. The results indicated that the concentrations of 10 and 30 µg/ml morusin significantly inhibited A549 cells and signs of apoptosis were observed. In addition, the wound‑healing assay results revealed that morusin inhibited cell migration. Flow cytometry analysis demonstrated that the rates of apoptosis were 16.46, 55.80 and 70.80% following treatment with 1, 10 and 30 µg/ml of morusin, respectively, and that the mitochondrial membrane potentials also decreased with the increase of morusin. Furthermore, morusin increased the antioxidant activities of the A549 cells. RT‑PCR analysis revealed that the expression levels of COX‑2 and VEGF were downregulated following morusin treatment. In conclusion, morusin significantly inhibited the proliferation of the lung cancer cell line A549, and may have affected the invasion and migration of the cells by downregulating the expression of tumor angiogenesis‑related genes.

Topics: A549 Cells; Apoptosis; Cell Movement; Cell Proliferation; Cyclooxygenase 2; Flavonoids; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; Membrane Potential, Mitochondrial; Vascular Endothelial Growth Factor A

This study was designed to validate the anticancer effects of morusin in human non-small cell lung cancer (NSCLC) cells. Morusin suppressed the cell growth and colony formation in a concentration-dependent manner in H1299, H460 and H292 cells. These anticancer activities were related with apoptosis induction proved by the accumulation of chromatin condensation, PARP cleavage, increase of sub-G1 phage and annexin V-positive cell population. Interestingly, signal transducer and activator of transcription 3 (STAT3) was dephosphorylated by morusin. Morusin suppressed the transcriptional activity of STAT3 and down-regulated the expression of STAT3 target genes. In addition, morusin inhibited the phosphorylation of epithelial growth factor receptor (EGFR), an upstream regulator of STAT3. The docking study showed that morusin directly binds to the tyrosine kinase domain of EGFR. Furthermore, the anticancer effects of morusin were consistently observed in erlotinib-resistant H1975 cells expressing L858R and T790 M mutant EGFR, suggesting that morusin can be used for the advanced NSCLC with acquired resistance to EGFR TKI. Taken together, our results demonstrate that morusin induced apoptosis in human NSCLC cells regardless of EGFR mutation status through inhibition of EGFR/STAT3 activation.

Topics: Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; ErbB Receptors; Erlotinib Hydrochloride; Flavonoids; Humans; Lung Neoplasms; Molecular Docking Simulation; Mutation; Phosphorylation; Protein Binding; Protein Kinase Inhibitors; STAT3 Transcription Factor